It is well known that a wide variety of organic materials are susceptible to oxidative degradation in the presence of air or oxygen, especially when at elevated temperatures. Such organic materials include, for example, gasolines, diesel fuels, burner fuels, gas turbine and jet fuels, automatic transmission fluids, gear oils, engine lubricating oils, thermoplastic polymers, natural and synthetic rubber, and the like. Over the years, considerable efforts have been devoted to discovery and development of compounds capable of minimizing the degradation of one or more of such materials. As conditions of use and exposure of such materials to various oxygen containing environments change over the years, the desire for new effective macromolecular oxidation inhibitors (a.k.a. antioxidants) continues. Also, the art benefits greatly if new and highly effective process technology is provided for producing known effective macromolecular oxidation inhibitors.
U.S. Pat. No. 3,673,091 discloses forming oxidation inhibitors by the reaction between 3,5-di-tert-butyl-4-hydroxybenzyl alcohol and aryl amines, carbazole, phenazines, or acridines. Unfortunately, the resultant reaction product is a complex mixture containing large quantities of unreacted amine starting material and in which the desired products are formed in low yields.